Devices for displaying information



Oct. 15, 1963, L. LE GOFF 3,106,794

DEVICES FOR DISPLAYING INFORMATION 4 Sheets-Sheet 1 Filed Aug. 1, 1961 I48a 34/ L I 1:3 2

Oct. 15, 1963 L. LE GOFF 3,106,794

DEVICES FOR DISPLAYING INFORMATION Filed Aug. 1. 1961 4 Sheets-Sheet 2Oct. 15, 1963 f L. LE GOFF 3,106,794

DEVICES FOR DISPLAYING INFORMATION Filed Aug. 1, 1961 4 Shegts-Sheet 5F164 36 7 FIG. 5 t as as a as, 5 3 a 06L 6 L. LE GOFF 3,106,794

DEVICES FOR DISPLAYING INFORMATION Filed Aug. 1, 1961 4 Sheets-Sheet 4F168 c4 "1 I I I I I I I I I I I 'l I I I I United States Patent Ofi icePatented Get. 15, 1963 3,106,794 DEVICES FUR DISPLAYING KNFGRMATIONLucien Le Golf, Asnieres, Seine, France, assignor to Societe Anonymedite: Societe dElccn'icite More, Paris, France, a French company FiledAug. 1, 1961, er. No. 128,473 Claims priority, application France Aug.2, 196% 9 Claims. (Cl. 49-28) The present invention relates to devicesfor displaying information and particularly to those enablinginformation to be displayed and easily read in lighted areas, I

such as stations, airports, racecourses, etc.

In such lighted areas, it is necessary that the inscriptionsconstituting the information be shown in a light colour on a darkbackground.

Different types of display devices fulfilling the above mentionedcondition are already known. For example, certain devices useinterchangeable placards but it is then necessary to have at onesdisposal a large number of placards and to provide an auxiliary devicein order to put them in place. Or again, devices are known comprisingdrums on the circumference of which there are painted, for example, thenumbers from 0 to 9 or the letters of the alphabet, one single figure orone single letter appearing at a given moment in a window of anindicator board behind which a drum is located. It is rarely possible touse such letter devices by reason of the great bulk of the drums.

It has also previously been proposed to use display devices in which thedisplay surface is formed by the juxtaposition of elementary surfacescapable of assuming one of at least two colours, e.g. a bright colourand a dark colour, each elementary surface being that of a membercomprising a magnetically polarised movable member capable of occupyingone of at least two positions according as to whether an externalcontrol member gives it a magnetic polarity in one direction or theother.

Display devices of this latter type, however, have not up to now formedthe object of a practical application because of the technologicaldifiiculties encountered in industrially manufacturing the displayelements which, in juxtaposition, form the display surface.

The present invention relates to the last-mentioned form of displaydevice, and has for an object to provide a display element of a new typewhich may be economically manufactured and which ensures absoluteoperational security.

A display element according to the invention comprises an elementarycylindrical casing with a geometrical cross section allowing, byjuxtaposition, the formation of a mosaic, (that is to say they may betriangular, square, rectangular or hexagonal), the front observationface of which is transparent, two magnetic stabilisation rings, onearranged on the side of the observation face and the other on the sideaway from this face, a piston in which is located a magnet, the magneticmoment of which is arranged parallel to the axis of the piston and whichhas a coloured face directed towards the observation face of the casing,this piston being mounted so as to be capable of being displaced insidethe cylindrical casing, and a liquid of a different colour from that ofthe coloured face of the piston and filling the space inside the casingwhich is vacated by the piston, means being provided to allow the freecirculation of the liquid during the movements of the piston.

The invention also relates to other characteristics relating both to theconstruction of the display element itself and to the control of displaydevices formed by the juxtaposition of display elements.

In order that the invention may be more clearly understood, variousembodiments thereof will now be described, by way of example, withreference to the accompanying drawings, in which:

FIGURE 1 is an isometric projection of a particular embodiment of adisplay element according to the invention;

FIGURE 2 is a sectioned plan of a display device according to theinvention;

, FIGURE 3 is a diagrammatic plan view of the arrangement of themagnetic control members of the magnetically polarised movable elements;

FIGURE 4 is a longitudinal section of a group of seven display elementsof a more elaborate embodiment forming a column;

FIGURE 5 is a section along the line V-V of the group of elements shownin FIGURE 4;

FIGURE 6 is a section along the line VI-VI of FIG- URE 4, on an enlargedscale, of one of the elements of the group of elements;

FIGURE 7 is an isometric projection of a particular member used formounting each member of the group and FIGURE 8 is a circuit diagram ofthe cancelling and inscribing circuits for the information on a displaydevice according to the invention.

Referring to FIGURE 1, the display device comprises a display surfaceformed by the juxtaposition, in a matrix comprising rows L L L L andcolumns C C C of elementary square-shaped surfaces.

According to this example, the cells of the matrix are bounded byhorizontal magnetic plates 8 held together by two assemblies of verticalmagnetic plates 9a and 9b, one arranged towards the front of and theother towards the rear of the display surface.

Each cell encloses a display element 16 comprising a hollow body 11 oftransparent material with a square cross section, terminating at thefront in a lens 12 and at the rear in stopper 13.

A magnet 14 forming a piston with a circular section can move freely toand fro inside the square-section bore of the body 11. The front face ofthe piston 14, constituting the north pole N of the magnet for example,is painted white and is the same shape as the inner face of I the lens12. The remaining free volume inside the body 11 is filled with a blackliquid 15.

The function of this embodiment may easily be understood; according asto whether a north or south pole is applied to the rear of a cell, thecorresponding piston 14 will be pushed forward against the lens 12 whichwill then appear white, or drawn back towards the rear against the back13 and then the lens 12 will appear black by reason of the black liquidwhich will then mask the remote white face of the piston 14.

By combining in any suitable manner the two different possiblecolorations of the elementary display surfaces, it may be seen that anydesired information may be caused to appear on the observation surface.

The vertical metal plates 9a and 9b serve to stabilise the two possiblepositions of the pistons 14.

In the case of the previous example, in which the cells are arranged ina matrix in orthogonal columns and rows, it may be seen that thisarrangement allows the display surface to be set to zero and to recordin a very simple manner.

FIGURE 2 shows the assembly of a display surface manufactured accordingto the invention and of an associated device for setting the apparatusto zero and for recording information.

The display surface A, such as that formed by the juxtaposition ofparallel surfaces as shown in FIGURE 1, is mounted at the front of acasing 16. In FIGURE 2 may be seen, in plan, the successive columns C C3 C C etc., each formed by the assembly of several vertically arrangeddisplay elements.

Behind the rear face of the display surface 2 a plurality ofelectro-magnets 17 may be displaced, said magnets being verticallyarranged so that their poles P P P P etc., are located on the samecolumn and spaced out in accordance with the rows such as L L L L(FIGURE 1) etc., of the display surface as shown in FIGURE 3.

The electro magnets 17 are mounted on a carriage 18 which can bedisplaced parallel to the rear face of the display surface A. To thisend, the carriage it is guided by rollers 19 rolling along the rails 26and is integral with a nut 21 in which a screw 22, driven by a belt andpulley transmission 23 from a motor 24, is rotatable.

A suitable electrical control circuit controls the rotation of the motor24, detects the position of the carriage 18, reads a registrationsupport upon which is recorded the information to be displayed, andconsequently sends successively, column by column, pulses with suitablepolarities to the electro magnets 17 in order to display the desiredmessage.

FIGURES 4 to 7 show a more elaborate embodiment of a group of elementsaccording to the invention. These elements are of a similar type tothose shown in FIGURE 1.

It has been considered that, for the majority of the uses of a displaysurface, it is sufficient to provide symbols, figures and letters, theindication of which is contained Wtih the aid of juxtaposed columns ofgroups of seven display elements.

Thus, there has been shown in FIGURES 4 to 7 such a group of sevenelements, it being understood that a horizontal strip of a displaydevice intended to receive a line of writing will be formed by thejuxtaposition of a large number of vertical groups of seven elements.

The group is contained in a casing, comprising a base provided withpartitions 31 forming seven cells 32, and a cover 33 which encloses thepartitions 31 and the base 30 and is made of a transparent material. Thebase 30 has lugs 34 allowing the groups to be fixed upon a commonsupport. The cover 33 is stuck or welded on to the base 30. It isprovided with a filler opening 35 which may be closed by a threaded plug36. The front face of the cover 33 forms an optical lens, as shown inFIGURE 6.

Each square cross section cell 32 of the group corresponds to a displayelement. The bottom of each cell has a circular reinforcement in whichis located a magnetic disc or plate 37 held in place by a non-magneticperforated plate 38. The plate 38 is itself held in place by the base ofa jacket 39 shown in perspective in FIG- URE 7.

The jacket 39 comprises an inner jacket 4% which is non-magnetic and is,for example, made of copper, on which are secured a front or forwardstabilising magnetic ring 41, and a rear stabilising magnetic ring 42.By front or forward is meant that side of the observation surface of thecover '33 located on the right in FIG- URE 4, and by rear the oppositeside located on the left in FIGURE 4. The assembly of the jacket 40 andthe rings 41 and 42 has a longitudinal slot 43, the function of whichwill hereinafter be described. Two diametrically opposed retainer slots44 are located towards the front of the jacket 39 and co-operate withtwo vertical strips 45 the curved ends of which are retained in securingrecesses 46 formed respectively in the upper and lower surfaces of thetwo end partitions 31 of a group. Finally the jacket 39 has at its basetwo diametrically opposed recesses 47 each arranged opposite the cornersof the square cross-section cell and the function of which will behereinafter described.

The piston 43 is capable of being displaced inside the jacket 39. Thepiston 48 encloses a cylindrical magnet 49, the north pole N of which isdirected forwards and 4 the south pole S backwards for example. Thefront face 48a of the piston 48 is a light colour, for example white,and has a very small radius of curvature, as has been shown in FIGURE 6,so that it cannot stick against the fiat inner surface of the cover 33.Generally the front face 43a of the piston 48 will be given a shape anddimensions suitable clearly to show the outline of the letters orsymbols. The shape of this forward face could, according torequirements, be triangular, square, rectangular, with or without thecorners cut off, or hexagonal.

In the case in which it is required to make use of letters or symbols oflarge size, a display device will be used in which the axes of themagnets such as 49 actuating the pistons such as 48 will form a networkwith larger meshes than in the example shown. It would then only benecessary sufficiently to enlarge the front faces 48a of the pistons 48to re-establish the continuity of the outline.

Finally, a coloured liquid 50, for example a black liquid, fills theinside of the casing formed by the base 30 and the cover 33. A smallspace is left free of liquid above the group of elements adjacent thefiller opening 35 in order to allow thermal expansion of the liquid. Thenature of this liquid is selected so that its different characteristicsof expansion, freezing, evaporation, chemical behaviour with regard tomaterials used, etc., are acceptable in relation to the conditionsimposed.

The method of operation of this embodiment of a display element iseasily understood. According to whether a south or north pole is appliedto the rear of a cell 32, the corresponding piston 38 is pushed forwardagainst the inner surface of the cover 33 forming a lens, which thenallows the white colour of the front face 48a of the piston to be seen,or it is drawn back against the base 33 and the face visible at thisplace of the cover 33 then appears black by reason of the black liquid50 which masks the remote white face 48a of the piston 48.

The front magnetic rings 41 on the one hand, and the rear rings 42co-operating with the magnetic disc 37 on the other hand, ensure thestability of the two possible positions of the piston 48 by magneticcoupling with the magnet 49 enclosed by the piston. The longitudinalslot 43 in the jacket 39 avoids any short circuit of the magnetic flux.

The recesses 47 allow the coloured liquid 50 to be admitted or tocirculate into or out of the interior of the jacket 39 according as towhether the piston 48 is travelling towards the covcr 33 or away fromit. It is clear that, as the cell is of square cross section and thepiston 43 is of circular cross section, the colored liquid can freelycirculate in the free spaces between the piston and the walls of thecell along the four edges of the cell 32; these free spaces communicateby the recesses 47 with the volume which is limited between the base 30and the rear face of the piston 48.

Of course, it is possible to use a jacket 39 which is of square section.The piston 48 would then be guided in this jacket only by fourgeneratrices. In this case, it would no longer be necessary to providerecesses 47 since the coloured liquid could freely circulate along thefour angles or edges of the square jacket.

As for the possibility of the free movement of the piston within thecoloured liquid in which it is immersed, this is obtained either, asshown above, by leaving sulficient clearance between the piston and theinner walls of the casing along which it is guided, or by providing oneor more longitudinal channels in the piston itself through which theliquid may circulate, or again by providing such channels in the wallsof the casing. In brief, it is only necessary to provide channelsensuring communication between the above defined volume which is limitedbetween the base 30 and the rear face of pistons 48 and the volumebetween the forward face of pistons 48 and the cover 33.

With the aid of several vertical groups of display eleaware ments of thetype described above, it is possible to form columns C C C C etc., on anindicator board such as that shown in FIGURE 2.

As has been stated above with regard to FIGURE 2, behind the rear faceof the display surface A a plurality of electro-magnets 1-7 may bedisplaced, said magnets being vertically arranged so that their poles PP P P etc., are located on the same column and have a spacing betweenthem corresponding to that of the rows such as L L L L etc., of thedisplay surface, as shown in FIGURE 2.

As has been described above, the electro-"magnets 17 are mounted on acarriage 18 which may be displaced parallel to the rear face of thedisplay surface A. The carriage .18 is driven by a motor 24.

Referring to FIGURE 8, an embodiment of an electrical control circuitwill now be described, said circuit serving to control the rotation ofthe motor 24, to detect the position of the cairiage 18, to read arecording support upon which the mesage to be displayed is recorded, andconsequently to send pulses successively, column by column, withsuitable polarities, to the electro-magnets 17 so as to display therequired message.

The circuit is fed from an AC. supply source G which is connected bymeans of a conventional starter switch M and a supply contact m to theprimary winding of transformer Tr.

Secondary windings s1 and s2 of this transformer respectively feed twofull-wave rectifier bridges, Pi and P2, which deliver direct voltageswith different values to the terminals B1, B2 and B3.

The messages intended to be displayed on the indicator board arepreviously recorded in the form of perforations on a tape ofconventional type which is not shown in FIGURE 8. This tape is read in aconventional reading device diagrammatically indicated in FIGURE 8 bythe rectangle L drawn in broken lines. Inside this rectangle is shownthe winding AB of the electro-magnet effecting the step-by-stepadvancement of the tape. Reading contacts 01, c2, c3 07 have been showncorresponding to the seven possible positions of the perforations in acolumn arranged transversely of the tape. It will thus be understoodthat for a given position of the tape in the reading device, the readingcontacts c1 to c7 are closed or open according as to whether they are atthat moment respectively scanning a perforated or unperforated positionon the tape. Then, when the winding AB is excited the tape advances byone step, and the subsequent recording column is read.

The advancement of the record tape, column by column, must besynchronised with the displacement or" the column of electro-magnets 17(FIGURE 2) successively in front or" the different columns (Cll, C2, C3,etc.) of display elements. To this end, the winding AB is fed by thefollowing circuit: Terminal Bi; synchronisation contact cs, which isclosed each time that the column of the electro magnets 17 is mid-waybetween two successive columns of display elements; winding AB; andterminal B2. The contact cs is actuated, for example, in the followingmanner: The movable portion of the contact cs is connected to move witha roller r (FIGURE 8) which moves longitudinally with the carriage l8(FTGURE 2) and is flexibly forced to roll over a saw-toothed member 51(FIGURE 8) secured to the structure 16 (FIGURE 2) of the apparatus. Thecontact as is shunted by a seriesconnected resistance and condensercircuit 52 constituting a spark-suppressor. Thus, upon each excitationof the winding AB, brought about by the closure of the contact cs, therecord tape is advanced by one column in the reading device L. Eachtrough of the saw-toothed member corresponds with a column of displayelements.

At the moment when a given column of the record tape is read, or after apredetermined delay to allow for the excitation of the electro magnetsand to compensate for the mechanical and electrical inertia of theapparatus and the circuits, certain of the contacts 01 to 07,corresponding to the perforations in the tape, are closed Whilst theothers, corresponding to non-perforated parts of the tape, remain open.

The contacts at to 07 are each connected in series with the winding of acorresponding relay R1 to R7; and the seven circuits: contact cl windingR1; contact 02 winding R2; etc., contact c7 winding R7, are connected inparallel between the terminals B2 and B3.

The relays R1 to R7 respectively control the contacts r1 to r7. In theposition of rest, as shown in FIGURE 8, the contacts r1 to r7 connectone end of the display electro magnets 17.1 to 17.7 to the terminal B1via a resistance 53. In the operative position, the contacts r1 to 17connect this end of the electro magnets 17.1 to 17.7 to the terminal B3.The other ends of the electro magnets 17.1 to 17.7 are connected incommon to the terminal B2.

FIGURE 8 diagrammatically shows the magnetically polarised movablemembers 48.1 to 48.7 which are capable of occupying one or other of twostable positions according to the direction in which current is flowingin the corresponding electro-magnet 17.1 to 17.7.

The method of operation of this circuit is simple to understand: when aperforation is read, it closes one of the contacts cl to 07, e.g.contact cl. The corresponding relay R1 is then excited and operates itscontact r1. The display electro-magnet 17.1 is then connected betweenthe terminals B2 and B3 and puts the element 48.1 in a suitable positione.g. that which causes its White surface to appear.

On the other hand, if there is no perforation the corresponding contacte.g. the contact c2 remains open. The relay R2 is thus not excited andleaves its contact 1-2 in the rest position. The electro-magnet 17.2 isthus connected between the terminals B2 and B1 and leaves the element48.2 in its second stable position, i.c. that it causes an elementaryblack surface to appear.

Reading of the tape and the inscription of its message upon the displayelements is thus carried out successively column by column.

It is convenient if the display electro-magnets 17.1 to 17.7 areenergised at the moment-at which they are located substantially facingthe display elements and are tie-energised when they occupy intermediatepositions between these display elements. To this end, a series circuitcomprising a supply relay RA, a resistance 54 and a rectifier 55 isconnected in parallel with the tape moving winding AB. Moreover, aseries circuit comprising a condenser 56 and one of the contacts m2controlled by the relay RA is connected in parallel with the relay RA. Aresistance $7 is provided and is connected across the condenser 56 whenthe contact m2 operates.

The circuits described above operate in the following manner: when thecarriage carrying the cancelling and inscribing electro magnets 17.1 to17.7 are moved in front of the saw-toothed member 51, one column of therecord tape is read and the corresponding message is displayed upon acolumn of display elements when the roller r which is moved with saidcarriage is located in a trough in the saw-toothed outline and when,therefore, the contact cs is open. After one column has been inscribed,the carriage and the roller r continuing to move, the roller r rises upan inclined edge of one tooth of the saw-toothed profile and ensures theclosing of the contact cs which thus takes place when the displayelectro magnets 17.1 to 17.7, which are always excited as a function ofthe perforations of the column of the recording tape being read at thismoment, are located in an intermediate position between two columns ofdisplay elements, but, however, nearer thecolumn of elements upon whicha notice is to be displayed. The contact cs, being closed, causes theexcitation of the winding AB, as explained above, and thus causes theadvancement by one step of the record tape in order that the followingcolumn may be read. This is not, however, carried out at this momentfor, at the same time, as the winding AB is excited, the relay RA isalso excited with a delay determined by the resistance :74 and thecondenser 56; in practice, the relay RA is excited immediately after thetape has been moved on by one step. The contact m1 then opens and cutsthe connection between the alternating supply source G and thetransformer Tr. The direct voltages at the terminals B1, B2 and B3 thuscease, and the rest of the circuits are, therefore, inoperative. Theoperation of the contact m2 allows the condenser 55 to be dischargedinto the resistance 57 which has the effect of keeping the relay RAmomentarily excited. In practice, the relay RA is dcenergised and thusallows its contact ml to fall back effectively giving rise to thereading of the following column of the tape and the correspondingregistration of the subsequent column of the display elements when thecolumn of display electro-magnets 17.1 to 17.7 occupies an intermediateposition between two successive columns of display elements but alwaysnearer the column upon which a message is to be displayed.

I claim:

1. Display device comprising a casing, a plurality of juxtaposed displayelements in said casing, each display element comprisin a magneticallypolarised movable member in the casing for sliding movement in adirection parallel to the magnetic axis of the member the casing beingfilled with a liquid and being provided with a transparent viewingsurface opposite a first end of said movable member, said first endhaving a color difierent from that of the liquid, said movable memberbeing movable between a first position in which said first end isadjacent said viewing surface to be visible therethrough and a secondposition in which said first end is spaced from said surface and is notvisible through said liquid, magnetic control means for selectivelycausing said movable member to move between said positions, and passagespermitting circulation of the liquid upon movement of said movablemember.

2. Device as claimed in claim 1 comprising two magnetic stabilisingmembers arranged respectively to stabilise the movable member in theposition to which it is moved.

3. Device as claimed in claim 2, wherein the two magnetic stabilisationmembers are rings each having a longitudinal slot, the device furthercomprising a cylindrical jacket of non-magnetic material supporting therings within which the movable member slides.

4. Device as claimed in claim 3, wherein the cylindrical jacket with thetwo magnetic rings is provided with recesses arranged to allow thecolored liquid to circulate during the movement of the piston.

5. Device as claimed in claim 4 comprising magnetic plates, one for eachdisplay element located in the casing opposite the end of the respectivemovable member which is remote from the viewing surface, the platesco-operating with the adjacent magnetic stabilisation ring.

6. Display device as claimed in claim 1, wherein the movable membersslide in separate elementary compartments in the casing with the firstends of the members disposed behind a transparent wall of the casing,each compartment being of angular cross section and having disposedtherein a cylindrical jacket of non-magnetic material carrying twomagnetic stabilisation rings adjacent opposite ends thereof, and whereineach of the movable members comprises a piston slidable in said jacket,said jacket being provided with openings to allow the liquid tocirculate into and out of the jacket during movement of the piston.

7. Display device as claimed in claim 1, wherein the display elementsare arranged in orthogonally disposed columns and rows, the magneticcontrol means being a column of magnetic control members, equal innumber to the number of display elements in one colunm, the column ofmagnetic control members being arranged behind the display elements andmounted for movement along the back of the display device so as to passbehind successive columns of display elements in turn, means fordisplacing the magnetic members stepwise to be positioned behind eachcolumn of display elements in turn, a record support adapted forrecording in a series of columns the indications given by the variousdisplay elements, means for advancing said record support in step withthe movement of the column of magnetic control members, means forsuccessively reading the columns of the record support, and means forcorrespondingly energising the magnetic control members in accordancewith said readings, the device further including an electricalsynchronizing circuit comprising a contact, means for commencing anopening and closing cycle of said contact when the magnetic controlmembers are located substantially midway between two successive columnsof display elements, and means responsive to the opening and closing ofsaid contacts for effecting advancement of the record support and forenergizing a circuit for transferring the readings of a column on therecord support to the magnetic control members when the column ofmagnetic control members is opposite a column of display elements.

8. Device as claimed in claim 7 comprising a roller which moves with thecolumn of magnetic control members and rolls upon a fixed member with asaw-toothed outline for synchronizing said contact, the teeth on saidfixed member having a pitch equal to the spacing of the columns ofdisplay elements.

9. A display element comprising a casing, a magnetically polarisedmovable member having a magnetic axis and mounted for sliding movementin a direction parallel to the magnetic axis in the casing, said casingbeing filled with a liquid and provided with a transparent viewingsurface opposite a first end of said movable member, said end having acolor different from that of the liquid, said member being movablebetween a first position in which said first end is adjacent saidsurface and a second position in which said end is spaced from saidsurface, two magnetic stabilising rings respectively arranged tostabilise the movable member in the position to which the movable memberis moved, and passages permitting circulation of the liquid when saidmovable member is moved.

References Cited in the file of this patent UNITED STATES PATENTS

1. DISPLAY DEVICE COMPRISING A CASING, A PLURALITY OF JUXTAPOSED DISPLAYELEMENTS IN SAID CASING, EACH DISPLAY ELEMENT COMPRISING A MAGNETICALLYPOLARISED MOVABLE MEMBER IN THE CASING FOR SLIDING MOVEMENT IN ADIRECTION PARALLEL TO THE MAGNETIC AXIS OF THE MEMBER THE CASING BEINGFILLED WITH A LIQUID AND BEING PROVIDED WITH A TRANSPARENT VIEWINGSURFACE OPPOSITE A FIRST END OF SAID MOVABLE MEMBER, SAID FIRST ENDHAVING A COLOR DIFFERENT FROM THAT OF THE LIQUID, SAID MOVABLE MEMBERBEING MOVABLE BETWEEN A FIRST POSITION IN WHICH SAID FIRST END ISADJACENT SAID VIEWING SURFACE TO BE VISIBLE THERETHROUGH AND A SEC-